Brett Braker
MET496
April 28th, 2011
Individual Performance Objectives

Show the importance of temperature-controlled
molding in thermoforming.

Prove that HDPE can be a relevant material to use in
thermoforming, instead of just amorphous materials.

Get project results by spring break, ± one week

Create a lab for future curriculum
Purpose

Almost all of thermoforming industry uses
amorphous materials

Use molds that are not temperature-controlled

Material options = Better quality parts
Material







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

50 High Density Polyethylene sheets
22.5” (MD) x 40” (TD) x 0.125”
Levant finish on top, smooth bottom
285-385°F forming temp, 330°F optimum
170°F ejection
Density: 0.0345 lb/in3 (0.955 g/cc)
66.3 Shore D hardness
Ultimate Tensile Strength: 3,800 psi
Tensile Yield Stress: 3,829 psi
Deflection temp with 66 psi: 166.5°F
Grid Layout
Original Idea
 Penn College Printing Department
 Pat Bundra
 Screen Printing

Non Temperature-Controlled Mold
Renshape 472 Medium Density
Polyurethane Board (REN)
 Wooden base, machined Polyurethane core
 Exact same dimensions as aluminum mold
 15.25” x 33.125” x 4.2”

Renshape Cycle

Bottom platen

Material Build-up

Stretching

Material Properties
Renshape Cycle
Renshape Cycle
Top platen
 Machine settings

Renshape Cycle
“Perfect” cycle
 Rails too close
 Mold too deep
 Ovens too hot

Production-Style Run
10 parts
 Continuous cycle
 Measurements

 Temperatures
 Aluminum Jig
 Thicknesses
 2 minutes after forming
 24+ hours after forming
Temperature Measurements

Mold
 Front
 Top
 Back
Sheet temp before and after forming
 Room temperature
 Humidity
 All taken with infrared gun

Aluminum Jig Measurements
15.875” x 33.500”
 Corner 3-4
 Height

 5.562”
 5.562 – x = h
 Jig thickness
 Aluminum blocks
 Meter stick height

Dial calipers
BL
8
7
6
9
5
10
4
FL
1
2
3
Thickness Measurements

Drill with hole saw attachment
 1-inch holes
Left, Right, Front, Back, and Top of part
 2 minutes – Left side
 24+ hours – Right side
 Discs
 Dial calipers

Measurement Formulas
After jig measurements
 Match corresponding points (1-8, 6-3, 5-9, etc.)
 Take combination of both and subtract from jig
dimension

 Y1 = 15.875 – (0.1025 + 0.4865)
 Y1 = 15.2860”
Points show warpage
 Y1 shows shrinkage

Renshape Mold Production

I.R. eye – 370°F
 Heating – 120 seconds

Cooling – 180 seconds
Renshape Production Results
Renshape Production Results
Renshape Production Results
Renshape Production Results
Aluminum Mold Production

I.R. eye – 370°F
 Changed to 360°F before Sheet 5

Cooling time – 100 seconds
 Changed to 120 seconds before Sheet 4
 Changed to 150 seconds before Sheet 5
 Changed to 130 seconds before Sheet 7
 Changed to 120 seconds before Sheet 8
 Changed to 110 seconds before Sheet 9

Circulator temp – 200°F
Aluminum Mold Production Results
Aluminum Mold Production Results
Aluminum Mold Production Results
Aluminum Mold Production Results
Renshape vs. Aluminum
REN
Dimensions
Y1
Y2
Y3
X1
X2
Z
Thickness
Front
Right
Back
Left
Top
2 mins
Average
15.2772
15.2703
15.2146
32.8077
32.7825
3.6531
Average
0.0728
0.0699
0.0693
0.0733
0.1280
72 hrs
Average
14.7679
14.6292
14.6189
32.5823
32.5545
3.5861
Average
0.0640
0.0541
0.0590
0.0536
0.1207
2 mins
St. Dev.
0.0737
0.0916
0.1027
0.0680
0.0604
0.1874
St. Dev.
0.0066
0.0072
0.0086
0.0105
0.0068
72 hrs
St. Dev.
0.0817
0.1319
0.1786
0.0540
0.0547
0.0854
St. Dev.
0.0063
0.0036
0.0056
0.0034
0.0037
Aluminum
Dimensions
Y1
Y2
Y3
X1
X2
Z
Thickness
Front
Right
Back
Left
Top
Al 2 mins
Average
15.1864
15.3429
15.2405
32.7307
32.6969
3.5513
Average
0.0939
0.0838
0.0846
0.0810
0.1029
Al 72 hrs
Average
15.0772
15.2224
15.1412
32.4864
32.5176
3.5266
Average
0.0903
0.0807
0.0918
0.0835
0.1083
Al 2 mins
St. Dev.
0.0532
0.0556
0.0387
0.0815
0.0234
0.0566
St. Dev.
0.0021
0.0064
0.0028
0.0021
0.0017
Al 72 hrs
St. Dev.
0.0629
0.0498
0.0494
0.0799
0.0627
0.0451
St. Dev.
0.0047
0.0054
0.0055
0.0044
0.0055
Renshape vs. Aluminum
Renshape vs. Aluminum
Renshape vs. Aluminum
OVERALL SHRINKAGE
REN
Width
Length
Height
72 hrs
3.816%
0.691%
1.836%
Aluminum
Width
Length
Height
72 hrs
0.719%
0.647%
0.696%
Renshape vs. Aluminum
Renshape vs. Aluminum
Grid Shrinkage
REN Aluminum
Top MD
+ 0.011" + 0.103"
Top TD
- 0.019" + 0.122"
Drawn MD
+ 1.508" + 1.005"
Drawn TD
- 0.025"
- 0.021"
Design Of Experiment
Cooling Time
Circulator Temp
I.R. Eye Temp
Run
Cooling Time
1
2
3
4
5
6
7
8
+
+
+
+
High
150
205
400
Circulator I.R. Eye
Temp
Temp
+
+
+
+
+
+
+
+
Low
90
170
330
A*M
A*O
M*O
A*M*O
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
Design Of Experiment
Renshape Tensile Testing
Renshape Mold Tensile Testing
Sample ID Yield Stress (psi) Max Stress (psi) Yield Elongation (%) Break Stress (psi) Modulus (psi) Max Energy (in*lb/in3) Max Elongation (%) TE Auto (%)
R4F
3100
3100
13.45
1949
39600
243
12.47
984
R7F
2670
2670
13.62
109.7
82500
278
13.27
160
R10F
2720
2720
15.62
1413
37300
305
15.62
848
R1B
2920
2920
12.73
1962
52300
272
12.73
687
R4B
3460
3460
14.09
1726
87600
331
12.46
409
R7B
2540
2540
14.11
582
69500
268
13.5
299
R10B
2520
2520
13.96
300
51600
244
12.84
550
R1L
3270
3270
16.79
2420
36700
372
16.79
1039
R4L
3150
3150
15.79
2190
35400
328
15.79
1039
R7L
2340
2340
0
N/A
67100
250
13.59
295
R10L
2580
2580
18.71
1899
29300
291
16.58
1039
R1R
2980
2980
16.61
2200
34000
307
15.57
1039
R4R
3180
3180
14.16
2520
38200
290
14.16
1013
R7R
2580
2580
17.9
1986
29000
296
16.85
1039
R10R
2320
2320
15.55
1731
26600
239
15.55
1039
St. Dev.
354.667
354.667
1.786
770.055
19907.615
37.599
1.645
332.731
Aluminum Tensile Testing
Temperature-Controlled Aluminum Mold Tensile Tests
Sample ID Yield Stress (psi) Max Stress (psi) Yield Elongation (%) Break Stress (psi) Modulus (psi) Max Energy (in*lb/in3) Max Elongation (%) TE Auto (%)
A7F
2750
2750
13.92
818
970000
302
13.81
101.2
A10F
2470
2470
13.566
703
59200
251
13.12
440
A4B
3220
3220
14.71
1335
89600
356
13.97
248
A7B
3510
3510
14.93
1046
1200000
403
14.44
435
A10B
2530
2530
14.7
37.6
81100
296
14.78
65
A4L
2870
2880
18.23
861
29600
322
17.12
1044
A10L
2260
2260
16.788
1606
25700
235
15.72
1039
A4R
2970
2980
18.63
2240
33400
332
16.53
1039
A7R
3040
3050
17.87
2170
334000
344
16.82
1039
A10R
2320
2320
15.799
1687
25900
265
16.84
1039
St. Dev.
405.221
406.613
1.848
691.224
434932.154
51.571
1.469
428.932
Renshape vs. Aluminum
Tensile Results
Yield Stress (psi)
Max Stress (psi)
Yield Elongation (%)
Break Stress (psi)
Modulus (psi)
REN
2822.50
2822.50
14.21
1644.66
48114.58
Aluminum
2759.58
2762.50
15.87
1208.13
282562.50
Max Energy (in*lb/in3)
Max Elongation (%)
TE Auto (%)
286.83
14.47
758.94
305.08
15.25
650.11
Conclusion

Temperature-controlled aluminum tooling
shows much more consistency with HDPE
than Renshape does.
 Much less warpage, shrinkage, and higher
dimensional stability as a result

HDPE needs a temperature-controlled mold
to be deemed relevant in the thermoforming
industry.
Individual Performance Objectives

Show the importance of temperature-controlled
molding in thermoforming.

Prove that HDPE can be a relevant material to use in
thermoforming, instead of just amorphous materials.

Get project results by spring break, ± one week

Create a lab for future curriculum
References





Defosse, Matthew. "Thermoforming." Modern Plastics
Worldwide World Encyclopedia 2006. Los Angeles, CA:
Canon Communications, 2006. 106. Print.
Harper, Charles A. Handbook of Plastic Processes.
Hoboken, NJ: Wiley-Interscience, 2006. Print.
Illig, Adolf, and Peter Schwarzmann. Thermoforming: A
Practical Guide. Munich: Hanser, 2001. Print.
Peacock, Andrew J. Handbook of Polyethylene:
Structures, Properties, and Applications. New York:
Marcel Dekker, 2000. Print.
"Sheet/Thermoforming Grade HDPE." www.matweb.com.
Material Property Data. Web.
<http://www.matweb.com/search/DataSheet.aspx?MatGU
ID=c35a0a3e740e424fad260a5da2c2b50a&ckck=1>.
Acknowledgements

John Bartolomucci, Pennsylvania College of Technology

Patrick Bundra, Pennsylvania College of Technology

Todd Chrismer, McClarin Plastics

Todd Kennedy, McClarin Plastics

Roger Kipp, McClarin Plastics

Aaron Lapinski, Pennsylvania College of Technology

Gary McQuay, Plastics Manufacturing Center
Questions?